3. Susan wants to visit her boyfriend, but she is busy now. ◊ Susan might visit her boyfriend if she wasn't busy now.

4. It rained heavily. His brother arrived at school on time. ◊ Although it rained heavily, his brother arrived at school on time.

5. How much does this television cost? ◊ What is the cost of this television?

6. We will cycle to school every day. We will keep fitter. ◊ If we cycle to school every day, we will keep fitter.

7. Jack often spends two hours painting the windows. ◊ It takes Jack two hours to paint the windows.

8. Learning English is not easy. ◊ It is not easy to learn English.

9. Why don't you plant some trees around your house to get more fresh air? ◊ How about planting some trees around your house to get more fresh air?

10. To do morning exercise every day is good for your health. ◊ It's good for your health to do morning exercise every day.